Identify which of the following plants form strobili and which exhibit isometric growth, and define trophic hormones.

Question 33:
Strobili are reproductive structures found in certain non-flowering plants, particularly Lycophytes.

• i. Marchantia: A liverwort, does not form strobili.
• ii. Lycopodium: A clubmoss, forms strobili.
• iii. Funaria: A moss, does not form strobili.
• iv. Selaginella: A spike moss, forms strobili.

The correct statements are ii and iv.

Question 34:
Isometric growth is a type of growth where all parts of an organism grow at the same relative rate, maintaining constant proportions.

• i. Organs appear to grow at the same rate as the rest of the body: This is characteristic of isometric growth.
• ii. It occurs in animals like fish and locust: These animals often exhibit periods of isometric growth.
• iii. The proportions of structure remain constant and changes in size is not accompanied by changes in shape or external form: This is the definition of isometric growth.
• iv. Organs grow at different rates from the entire body: This describes allometric growth, not isometric.

The correct statements are i, ii, and iii.

Question 35:
Trophic hormones are hormones that stimulate other endocrine glands to produce and secrete their own hormones.

• i. Growth hormone and prolactin: Growth hormone has some trophic effects, but prolactin is not primarily a trophic hormone for other glands.
• ii. Prolactin and FSH: FSH is a trophic hormone, but prolactin is not.
• iii. LH, TSH, and ACTH: Luteinizing Hormone (LH), Thyroid-Stimulating Hormone (TSH), and Adrenocorticotropic Hormone (ACTH) are all classic examples of trophic hormones.
• iv. ACTH and Human placental lactogen: ACTH is a trophic hormone, but Human placental lactogen is not.

The correct option is iii.

Question 36:
The heat loss center in the hypothalamus is activated when body temperature rises, promoting mechanisms to dissipate heat and reduce heat production.

• i. Increases vasoconstriction: This is a heat conservation mechanism.
• ii. Inhibits sweating and panting: This would reduce heat loss; the heat loss center stimulates these.
• iii. Increases thickness of air layer by contraction of hair muscles, making hair stand erect: This is a heat conservation mechanism (piloerection).
• iv. Decreases metabolic activities: Reducing metabolic rate decreases internal heat production, aiding heat loss.

The correct statement is iv.